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Tent Caterpillars

Tent Caterpillars

Malacosoma species

Insectalso: Eastern tent caterpillar, Forest tent caterpillar

Hairy spring caterpillars that build conspicuous silken tents in the forks of cherry, crabapple, and other trees and fan out to chew the leaves. Eastern tent caterpillars are mostly a cosmetic nuisance on healthy trees, but heavy feeding can defoliate and stress small or already-weak trees and ruin the look of a spring garden tree.

🔎 How to spot it

Look for hairy caterpillars up to about two inches long, with a solid white stripe down the back, bluish sides flecked with spots, and long pale hairs. The clearest sign is the silken tent built in the crotch where branches meet, which the caterpillars enlarge as they grow; this is different from fall webworm, whose tents sit at the branch tips later in the year.

🥀 Damage it causes

The caterpillars chew the leaves and can strip patches of a tree in spring, but healthy mature trees usually tolerate the loss and releaf, so the damage is mostly cosmetic and the unsightly tents. Small, young, or already-stressed trees, and fruit trees, can be more seriously set back, with reduced fruit and, rarely, dieback.

🛡️ Prevent it

Scout host trees, cherry, crabapple, apple, and others, in late fall and winter for the dark, shiny egg masses that ring small twigs, and prune them out or scrape them off. Keep trees healthy and vigorous so they shrug off spring feeding. Encourage the birds and parasitic insects that prey on the caterpillars.

🧯 If it is already here

Remove the tents by hand, wearing gloves, or wind them onto a stick, ideally in the cool of early morning or evening when the caterpillars are inside, and destroy them; do not burn tents on the tree, which harms the tree more than the caterpillars do. On small trees, the organic spray Bacillus thuringiensis (Bt) controls young caterpillars while they are under an inch long.

💡 Good to know

Eastern tent caterpillars appear early, in spring, with tents in branch forks, while the similar fall webworm shows up late, in summer and fall, with tents at the branch tips, an easy way to tell the two apart. On a healthy shade tree the damage is mostly an eyesore, so removing the tents by hand is usually all that is needed.

🌱 Plants it attacks

76 plants in the library can be attacked by this pest

American BasswoodAnjou PearAroniaAsian PearAunt Molly's Ground CherryBalsam PoplarBartlett PearBeach PlumBing CherryBlack Tartarian CherryBlack WalnutBosc PearBraeburn AppleChampagne LoquatChokecherryClimbing Prairie RoseContender PeachCoral Drift Groundcover RoseCornelian CherryCortland AppleCosmic Crisp AppleDamson PlumDillElberta PeachEnglish WalnutFantasia NectarineFlorence FennelFlowering DogwoodFuji AppleGala AppleGraham Thomas English RoseGranny Smith AppleHansa Rugosa RoseHardy KiwiHawthornHoney LocustHoneycrisp AppleIceberg Floribunda RoseIndian HawthornKnock Out RoseLicoriceMcIntosh AppleMethley PlumMister Lincoln Hybrid Tea RoseMontmorency CherryMoorpark ApricotMoringaMoss RoseNanking CherryNew Dawn Climbing RosePaper BirchPeace Hybrid Tea RosePink Lady ApplePossum Purple Passion FruitPrickly PearQuaking AspenQueen Elizabeth Grandiflora RoseQuinceRainier CherryRed AlderRed Delicious AppleRedhaven PeachRegent SaskatoonRoyal Heritage Lenten RoseSassafrasSea KaleSlippery ElmStanley PlumStinging NettleSugar AppleSugar MapleSweet Chariot Miniature RoseTexas Scarlet Flowering QuinceWhite AshWhite WillowWitch Hazel

For educational and informational purposes only. Pest control advice is general guidance drawn from university cooperative extension sources; always identify a pest positively and read and follow the label on any product before use, especially around food crops, children, and pets.